A conventional harmonic current compensator is connected in parallel with a harmonic generating load to a system power supply. The conventional harmonic current compensator detects a load current input to the harmonic generating load and extracts a harmonic component contained in the detected load current. The conventional harmonic current compensator generates a compensation current for compensating for the extracted harmonic component by controlling ON and OFF states of a switching device.
The conventional harmonic current compensator has a function of, when an instantaneous value of the compensation current reaches a predetermined value or greater, determining that excess current (hereinafter referred to as an overcurrent) flows and coming into a stopped state.
Examples of the conventional harmonic current compensator include a harmonic current compensator that addresses harmonics without impairing harmonic compensation, by limiting a compensation instruction for reactive power of a fundamental wave when an instantaneous value of a compensation current is a predetermined value or greater (see, for example, Patent Literature 1).